Hearing Conservation Program

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Hearing Conservation Program
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A. Background
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Noise

• Any unwanted sound--created by many different
  sources
• Traffic
• Industrial equipment and tools
• Music
• Gunfire exercises
• Ventilation
• Excessive noise--over time and certain
  levels--can cause hearing loss

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Noise Exposure

• Determined by
• Duration of exposure
• Type of noise
• Continuous
• Impulse
• Intensity
• Frequency

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Causes of Hearing Loss

• Age
• Disease (Middle or Inner Ear)
• Trauma
• Drugs
• Noise exposure

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B. How Hearing Loss Occurs
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Damage to the Ear

• Outer ear--
• Catches dirt and particles in the canal that
  contains cerumen or wax
• Middle ear--
• Has bones and ear drum which can rupture from
  sudden high sound pressure levels
• Inner ear--
• Has cochlea with tiny hair cells connected to
  nerves. Damage is irreversible

Middle ear
Cochlea
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C. Measuring Sound
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Terminology

• Frequency
• Measured in hertz (Hz) or cycles per second
• Determines how high or low the pitch sound
• Intensity
• Measured in decibels (dB)
• Determines how loud a noise sounds

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Other Information

• Ability to hear well depends on
• Pitch of the sound
• Age of the individual
• Distance from noise source
• Previous noise exposures
• Environment (surroundings)

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Other Information

• Sound level meters used to measure noise levels
• 20 Decibels (dB)--faint sound (like a quiet
  bedroom)
• 150 Decibels (dB)--F-14 at takeoff on flight deck
• Navy Industrial Hygiene Officers (IHO) conduct
  noise surveys

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D. Navy Hearing Conservation Program
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Program Objective

• The objective of the Hearing Conservation Program
  is to prevent hearing loss as a result of
  exposure to hazardous noise.

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Program Elements

• Identifying noise hazardous areas
• Engineering controls to reduce the hazard
• Posting of noise hazardous areas
• Providing hearing protection to personnel
• Medical monitoring (audiograms)
• Education and training

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E. The Program Elements
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Identifying Noise Hazardous Areas

• Limits for continuous noise exposure
• DOD 85 dB
• OSHA 90 dB
• Impact (Impulse) noise limit 140 dB
• 84 dB or less--OK for personnel 8 hours a day,
  five days a week with no ill effects.
• Above 84 dB--Navy considers noise hazardous

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Identifying Noise Hazardous Areas

• Sound level surveys conducted to determine which
  spaces routinely have
• Continuous noise gt84 dB
• Impact noise gt140 dB
• Survey documents retained onboard
• Readings repeated after overhaul or if new
  equipment added/changed
• Readings reviewed every 2 years as part of IH
  survey

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Engineering Controls

• Accomplished as part of
• New construction
• Overhaul
• SHIPALT
• IMA
• Applied to submarines to reduce waterborne noise

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Engineering Controls

• Noise can be decreased by changes in design or
  imposing controls
• Damping material or sound curtains around
  equipment
• Acoustical tiles for classrooms
• Rubber insulating pads at metal-to-metal
  interface
• Moving noise equipment to isolated location
• Engineering controls must be considered FIRST,
  prior to resorting to PPE

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Posting Noise Hazard Signs

• Used when engineering controls do not work, or
  are not feasible
• Use Yellow and Black signs to mark hazards
• Large signs for entire areas
• Small stickers for individual equipment
• Post areas as DOUBLE Hearing Protection Required
  if sound levels gt104dB

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Personal Protection

• Used as last resort--when exposures cannot be
  controlled by any other means
• Ear plugs and muffs
• Mechanically block noise from ear
• Rated for specific Noise Reduction Rating
  (NRR)--reduce decibel levels reaching the ear by
  the number listed on the package

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Personal Protection

• Ear plugs
• Fit into ear canal
• Fitted/Flanged types issued by Medical
• Disposable foam plugs dont require fitting--also
  have highest NRR (about 30dB)
• Ear muffs
• Fit over outer ear
• Have NRR of 24-28 dB
• Ear caps--like plugs with a head band--NRR of
  about 22 dB

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Personal Protection

• Double protection
• Required when continuous sound levels gt104dB
• Use combination of ear plugs and ear muffs
• Must be kept clean and in good condition
• Dirty plugs may cause infections
• Muffs with hardened seals DO NOT protect

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Medical Monitoring

• Baseline and routine testing required for all
  personnel working in noise hazardous areas
• All naval personnel given baseline audiogram when
  entering the service
• Annual audiograms given to personnel assigned
  work in noise hazardous areas
• Termination audiograms given to personnel when
  leaving the service